This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application entitled Digital Trunk Circuit Supporting Multiple Trunk Circuits earlier filed in the Korean Industrial Property Office on the 13th day of July 1998, and there duly assigned Serial No. 28129/1998, a copy of which is annexed hereto.
1. Technical Field
The present invention relates generally to a digital trunk circuit, and in particular, to a digital trunk circuit supporting multiple trunk circuits assembled in a single board.
2. Related Art
In a private branch exchange (PBX) system, a trunk circuit connected between a switching circuit and an office line, forms a speech loop for the office line. Such a trunk circuit can be divided into an analog trunk circuit, connected to a public switched telephone network (PSTN), for exchanging analog signals, and a digital trunk circuit, connected to an integrated services digital network (ISDN), for exchanging digital signals.
A digital trunk circuit in a primary rate group can be divided into four kinds of trunk circuits according to a transfer rate of digital signals and a D-channel signaling method. A trunk circuit supporting a transfer rate 1.544 Megahertz (MHz) is called a T1 trunk circuit, and a trunk circuit supporting a transfer rate 2.048 MHz is called an E1 trunk. In addition, the D-channel signaling method is divided into a channel associated signaling (CAS) method and a common channel signaling (CCS) method; a primary rate interface (PRI) controls a common channel signaling signal according to a link access procedure on the D-channel (LAP-D) signaling method. As a result, the digital trunk circuit can be divided into four kinds of trunk circuits, that is, a T1 trunk circuit, an E1 trunk circuit, a T1-PRI trunk circuit and an E1-PRI trunk circuit.
However, to allow the single board to support various trunk circuits, the board should include several framers for the respective trunk circuits and associated transceivers. In particular, to support the a primary rate interface (PRI) function, the board should include an HDLC (high level data link control) controller in addition to the framers and transceivers, causing an increase in number of the elements.
Furthermore, when the single board in which various trunk circuits are assembled, is installed in an exchange system of a country where only one of the T1 and E1 trunk circuits is selectively used, the unused trunk circuit is unnecessary. To remove the unused trunk circuit, elements for the unnecessary trunk circuit are uninstalled. However, in terms of maintenance and management, this may incur a greater loss, as compared with the case where the trunk circuits are manufactured in separate boards.
I have found that inefficient and undesirable arrangements of trunk circuits can be extremely inconvenient. Efforts have been made to improve data communication circuits.
Exemplars of recent efforts in the art include U.S. Pat. No. 5,077,735 for method for an Apparatus for Mutually Converting Different Signaling Systems issued to Myung et al., U.S. Pat. No. 5,790,676 for Radio Port Controller in a Wireless Personal Communications System issued to Ganesan et al., U.S. Pat. No. 5,799,019 for Circuit for Converting Frame Data issued to Kim et al., U.S. Pat. No. 5,708,703 for Wide Range Equalizer with Line Length Detection issued to Nagaraj, U.S. Pat. No. 5,623,491 for Device for Adapting Narrowband Voice Traffic of a Local Access Network to Allow Transmission over a Broadband Asynchronous Transfer Mode Network issued to Skoog, U.S. Pat. No. 5,060,227 for Digital Telephone Switch with Simultaneous Dual PCM Format Compatibility issued to Finley et al., U.S. Pat. No. 5,526,397 for Switching Transcoder issued to Lohman, U.S. Pat. No. 4,694,452 for Switching Configuration for a Telecommunications System in Particular a PBX System with Subscriber Lins, Trunk Groups, and Interface Modules issued to Beckinger et al., U.S. Pat. No.4,829,491 for Phased-Array Equipment issued to Saugeon et al., U.S. Pat. No. 4,499,461 for Circuit Arrangement for Centrally-Controlled Telecommunication Exchange Systems, Particularly for Time-Division Multiplex Telephone Exchange Systems, with Information Exchange Between PBX Devices issued to Schneider, U.S. Pat. No. 5,881,148 for T1 Channel Bank Control Process and Apparatus issued to Koenig et al., and U.S. Pat. No.5,892,768 for 10/100-Base Ethernet to T1/E1 HDSL Converter and Method of Operation issued to Jeong.
The above-referenced U.S. Pat. No. 5,892,768 issued to Jeng includes an Appendix A having a brief description of T1-raining and E1-framing, here incorporated by reference.
While the above recent efforts provide advantages, I note that they fail to adequately provide an efficient and convenient digital trunk circuit supporting multiple trunk circuits.
It is, therefore, an object of the present invention to provide a digital trunk circuit supporting multiple trunk circuits assembled in a single board.
It is another object of the present invention to provide a digital trunk circuit in which various trunk circuits are assembled in a single board, and even though only one of the trunk circuits is selected, the other trunk circuits are not unnecessary.
It is further another object of the present invention to provide a digital trunk circuit in which various trunk circuits are assembled in a single board, and maintenance and management can be made separately for the respective trunk circuits.
To achieve the above object, there is provided a digital trunk circuit supporting multiple trunk circuits assembled in a single board. A digital trunk circuit supporting multiple trunk circuits assembled in a single board. A trunk selector capable of being operated by a user, outputs trunk select information for selecting one of the multiple trunk circuits according to an operation of the user. A read only memory (ROM) stores drive programs for the respective trunk circuits. A framer and line interface serves as a T1 framer or an E1 framer according to a register value, and includes line interface nodes having a connection for the T1 framer or the E1 framer. A receiving transformer connected to an office line, receives a signal incoming from the office line. A transmission transformer connected to the office line, transmits a signal to the office line. A relay switch including a plurality of relays connected between the receiving transformer and the line interface nodes of the framer and line interface and between the transmission transformer and the line interface nodes, provides a receiving path between the line interface nodes and the receiving transformer and a transmission path between the line interface nodes and the transmission transformer, in response to relay drive control signals. A first processor determines a trunk circuit to be driven depending on the trunk select information output from the trunk selector, drives an associated drive program stored in the read only memory according to the determination result, generates a register value for determining an operation mode for a framer of the framer and line interface to provide the generated register value to the framer and line interface, and generates the relay drive control signals to provide the generated relay drive control signals to the relay switch.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: a digital trunk circuit being assembled in one board and supporting a plurality of specialized trunk circuits, said digital trunk circuit comprising: a trunk selector being operated by a user and outputting trunk select information for selecting one of said plurality of specialized trunk circuits according to an operation of the user; a read only memory storing a plurality of drive programs, each respective one of said plurality of drive programs driving a respective one of said plurality of specialized trunk circuits; a framer and line interface unit operating in an operation mode selected from a first operation mode and a second operation mode according to a register value, said framer and line interface unit corresponding to a T1 framer performing T1 framing when operating in said first operation mode, said framer and line interface unit corresponding to an E1 framer performing E1 framing when operating in said second operation mode, said framer and line interface unit including line interface means providing a connection corresponding to said T1 framer and said E1 framer, said framer and line interface unit including a plurality of line interface nodes; a receiving transformer being connected to an office line and receiving a signal incoming from the office line; a transmission transformer being connected to the office line, for transmitting a signal to the office line; a relay switch including a plurality of relays, said relay switch switching in response to relay drive control signals, said relay switch switching to connect said receiving transformer and said plurality of line interface nodes to provide a receiving path between said plurality of line interface nodes and said receiving transformer, said relay switch switching to connect said transmission transformer and said plurality of line interface nodes to provide a transmission path between said plurality of line interface nodes and said transmission transformer; and a first processor identifying a particular trunk circuit selected from among said plurality of specialized trunk circuits, said particular trunk circuit corresponding to said trunk select information output from said trunk selector, said first processor driving a particular drive program selected from among said plurality of drive programs stored in said read only memory, said particular drive program corresponding to said particular trunk circuit, said first processor generating said register value being output to said framer and line interface unit, said first processor generating said relay drive control signals being output to said relay switch.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: a digital trunk circuit being assembled in one board and supporting a plurality of specialized trunk circuits, said digital trunk circuit comprising: a trunk selector being operated by a user and outputting trunk select information for selecting one of said plurality of specialized trunk circuits according to an operation of the user; a read only memory storing a plurality of drive programs, each respective one of said plurality of drive programs driving a respective one of said plurality of specialized trunk circuits; a framer and line interface unit operating in an operation mode selected from a first operation mode and a second operation mode according to a register value, said framer and line interface unit corresponding to a T1 framer performing T1 framing when operating in said first operation mode, said framer and line interface unit corresponding to an E1 framer performing E1 framing when operating in said second operation mode, said framer and line interface unit including line interface means providing a connection corresponding to said T1 framer and said E1 framer, said framer and line interface unit including a plurality of line interface nodes; a receiving transformer being connected to an office line and receiving a signal incoming from the office line; a transmission transformer being connected to the office line, for transmitting a signal to the office line; a relay switch including a plurality of relays, said relay switch switching in response to relay drive control signals, said relay switch switching to connect said receiving transformer and said plurality of line interface nodes to provide a receiving path between said plurality of line interface nodes and said receiving transformer, said relay switch switching to connect said transmission transformer and said plurality of line interface nodes to provide a transmission path between said plurality of line interface nodes and said transmission transformer; a first processor identifying a particular trunk circuit selected from among said plurality of specialized trunk circuits, said particular trunk circuit corresponding to said trunk select information output from said trunk selector, said first processor driving a particular drive program selected from among said plurality of drive programs stored in said read only memory, said particular drive program corresponding to said particular trunk circuit; and a second processor mounted on said one board, said second processor reading said trunk select information output from said trunk selector to determine a selected trunk circuit to be driven, controlling said first processor according to the determination to execute said particular drive program stored in said read only memory, generating said register value being output to said framer and line interface unit, and generating said relay drive control signal being output to said relay switch.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: a digital trunk circuit being assembled in one board and supporting a plurality of specialized trunk circuits, said digital trunk circuit comprising: a trunk selector being operated by a user and outputting trunk select information for selecting one of said plurality of specialized trunk circuits according to an operation of the user; a read only memory storing a plurality of drive programs, each respective one of said plurality of drive programs driving a respective one of said plurality of specialized trunk circuits; a framer and line interface unit operating in an operation mode selected from a first operation mode and a second operation mode according to a register value, said framer and line interface unit corresponding to a first framer performing first framing when operating in said first operation mode, said framer and line interface unit corresponding to a second framer performing second framing when operating in said second operation mode, said framer and line interface unit including line interface means providing a connection corresponding to said first framer and said second framer, said framer and line interface unit including a plurality of line interface nodes, said first framing being different from said second framing; a receiving transformer being connected to an office line and receiving a signal incoming from the office line; a transmission transformer being connected to the office line, for transmitting a signal to the office line; a relay switch including a plurality of relays, said relay switch switching in response to relay drive control signals, said relay switch switching to connect said receiving transformer and said plurality of line interface nodes to provide a receiving path between said plurality of line interface nodes and said receiving transformer, said relay switch switching to connect said transmission transformer and said plurality of line interface nodes to provide a transmission path between said plurality of line interface nodes and said transmission transformer; a first processor identifying a particular trunk circuit selected from among said plurality of specialized trunk circuits, said particular trunk circuit corresponding to said trunk select information output from said trunk selector, said first processor driving a particular drive program selected from among said plurality of drive programs stored in said read only memory, said particular drive program corresponding to said particular trunk circuit; and a second processor mounted on said one board, said second processor reading said trunk select information output from said trunk selector to determine a selected trunk circuit to be driven, controlling said first processor according to the determination to execute said particular drive program stored in said read only memory, generating said register value being output to said framer and line interface unit, and generating said relay drive control signal being output to said relay switch.